Spontaneous transient inward currents and rhythmicity in canine and guinea-pig tracheal smooth muscle cells

Spontaneous transient inward currents (STICs) were recorded in canine and guinea-pig tracheal myocytes held at negative membrane potentials. STICs were Cl− selective since their reversal potential was dependent on the Cl− gradient and they were blocked by the Cl− channel blocker niflumic acid. STICs were insensitive to Cs+, charybdotoxin, and nifedipine. Ca2+-activated K+ currents often preceded STICs, suggesting that the STICs are Ca2+ …